Active matrix substrate, manufacturing method thereof, and image display device

Abstract

According to the first aspect of the present invention, a drain electrode and a pixel electrode are electrically connected to each other on a protective film formed on a semiconductor active layer, and thereby it is possible to easily connect the drain electrode and the pixel electrode to each other and to improve a yield.

What is claimed is: 
     
       1. An active matrix substrate comprising:
 a plurality of pixels which are arranged on a substrate and each of which includes a thin film transistor, 
 wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, 
 wherein a protective film is formed on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions, the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is connected to the pixel electrode on the protective film, a connection point between the drain and the pixel electrode is above the protective film, 
 wherein the plurality of thin film transistors are arranged in a straight line shape, 
 wherein a plurality of independent semiconductor active layers which respectively constitute the plurality of thin film transistors are arranged in parallel and in a straight line shape, and 
 wherein the protective film is continuously formed in a stripe shape over the plurality of semiconductor active layers so as to divide each of the plurality of semiconductor active layers into two exposed regions. 
 
     
     
       2. The active matrix substrate according to  claim 1 , wherein the protective film is formed in a forward tapered shape. 
     
     
       3. The active matrix substrate according to  claim 1 ,
 wherein the protective film is formed from an organic insulating material. 
 
     
     
       4. The active matrix substrate according to  claim 1 ,
 wherein the protective film is formed of a plurality of layers, and one layer of the plurality of layers coming into contact with at least the semiconductor active layer includes an inorganic insulating material. 
 
     
     
       5. The active matrix substrate according to  claim 1 , wherein the interlayer insulating layer is pigmented with a predetermined color. 
     
     
       6. The active matrix substrate according to  claim 1 , wherein the semiconductor active layer is formed from a metal oxide. 
     
     
       7. An image display comprising the active matrix substrate according to  claim 1 , wherein the image display is any one of a liquid crystal type, an organic electroluminescence type, and an electrophoretic type. 
     
     
       8. An active matrix substrate comprising:
 a plurality of pixels which are arranged on a substrate and each of which includes a thin film transistor, 
 wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, and 
 wherein a protective film is formed on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions, the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is connected to the pixel electrode on the protective film, and 
 wherein the protective film, is formed in a lattice shape for partitioning the pixels, and is formed so as to have a light blocking property. 
 
     
     
       9. A manufacturing method of an active matrix substrate including a plurality of pixels arranged on a substrate and each of which includes a thin film transistor, wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, the method comprising:
 forming the gate electrode on the substrate; 
 forming the gate insulating layer on the gate electrode; 
 forming the semiconductor active layer on the gate insulating layer; 
 forming a protective film on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions; 
 forming a layer formed from a conductive material on the protective film, the semiconductor active layer, and an entire surface of the gate insulating layer 
 wherein forming the layer is through patterning such that the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is left on the protective film; 
 forming the interlayer insulating layer on an entire surface of the substrate; 
 providing an opening portion in the interlayer insulating layer on the protective film; and 
 forming the pixel electrode on the interlayer insulating layer and electrically connecting the pixel electrode to the drain electrode, a connection point between the pixel electrode and the drain electrode is above the protective film, 
 wherein, in the forming of the protective film on the semiconductor active layer so as to divide the semiconductor active layer into the two exposed regions, the protective film is continuously formed in a stripe shape on each of the plurality of semiconductor active layers respectively constituting the plurality of thin film transistors so as to divide the semiconductor active layer into the two exposed regions. 
 
     
     
       10. The manufacturing method of the active matrix substrate according to  claim 9 , wherein the forming of the protective film includes:
 forming a first protective film on the entire surface of the substrate; 
 forming a second protective film so as to divide the semiconductor active layer into the two exposed regions; and 
 removing the first protective film exposed from the second protective film through etching. 
 
     
     
       11. A manufacturing method of an active matrix substrate including a plurality of pixels arranged on a substrate and each of which includes a thin film transistor, wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, the method comprising:
 forming the gate electrode on the substrate; 
 forming the gate insulating layer on the gate electrode; 
 forming the semiconductor active layer on the gate insulating layer; 
 forming a protective film on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions; 
 forming a layer formed from a conductive material on the protective film, the semiconductor active layer, and an entire surface of the gate insulating layer 
 wherein forming the layer is through patterning such that the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is left on the protective film; 
 forming the interlayer insulating layer on an entire surface of the substrate; 
 providing an opening portion in the interlayer insulating layer on the protective film; and 
 forming the pixel electrode on the interlayer insulating layer and electrically connecting the pixel electrode to the drain electrode, 
 wherein, in the forming of the protective film on the semiconductor active layer so as to divide the semiconductor active layer into the two exposed regions, the protective film is formed in a stripe shape on each of the plurality of semiconductor active layers respectively constituting the plurality of thin film transistors so as to divide the semiconductor active layer into the two exposed regions, and 
 wherein the protective film is formed in the stripe shape using a printing method. 
 
     
     
       12. A manufacturing method of an active matrix substrate including a plurality of pixels arranged on a substrate and each of which includes a thin film transistor, wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, the method comprising:
 forming the gate electrode on the substrate; 
 forming the gate insulating layer on the gate electrode; 
 forming the semiconductor active layer on the gate insulating layer; 
 forming a protective film on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions; 
 forming a layer formed from a conductive material on the protective film, the semiconductor active layer, and an entire surface of the gate insulating layer 
 wherein forming the layer is through patterning such that the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is left on the protective film; 
 forming the interlayer insulating layer on an entire surface of the substrate; 
 providing an opening portion in the interlayer insulating layer on the protective film; and 
 forming the pixel electrode on the interlayer insulating layer and electrically connecting the pixel electrode to the drain electrode, 
 wherein, in the forming of the protective film on the semiconductor active layer so as to divide the semiconductor active layer into the two exposed regions, a lattice-shaped light blocking protective film is formed on the semiconductor active layer so as to divide the semiconductor active layer into the two exposed regions and partition the pixels from each other. 
 
     
     
       13. A manufacturing method of an active matrix substrate including a plurality of pixels arranged on a substrate and each of which includes a thin film transistor, wherein the thin film transistor includes a gate electrode, a gate insulating layer on the gate electrode, a semiconductor active layer on the gate insulating layer, a source electrode connected to the semiconductor active layer, a drain electrode connected to the semiconductor active layer, a pixel electrode connected to the drain electrode, and an interlayer insulating layer for insulating the source electrode from the pixel electrode, the method comprising:
 forming the gate electrode on the substrate; 
 forming the gate insulating layer on the gate electrode; 
 forming the semiconductor active layer on the gate insulating layer; 
 forming a protective film on the semiconductor active layer so as to divide the semiconductor active layer into two exposed regions; 
 forming a layer formed from a conductive material on the protective film, the semiconductor active layer, and an entire surface of the gate insulating layer 
 wherein forming the layer is through patterning such that the source electrode is connected to one of the two exposed regions, the drain electrode is connected to the other of the two exposed regions, and the drain electrode is left on the protective film; 
 forming the interlayer insulating layer on an entire surface of the substrate; 
 providing an opening portion in the interlayer insulating layer on the protective film; and 
 forming the pixel electrode on the interlayer insulating layer and electrically connecting the pixel electrode to the drain electrode, 
 further comprising performing plasma irradiation for a region exposed from the protective film on the semiconductor active layer, the plasma irradiation performed after the forming of the protective film.